What are some ways that a group of several agile and fit individuals can be (mortally) threatened in a large forest in the autumn? Temperate climate, realistic setting , low magic - I would prefer to avoid "a village of kobolds attacks you". Even "animal attack" is a little unrealistic for me as animal-on-human attacks are quite rare unless provoked.

Context:
The group is going in there to find some bandits. I want to make the place dangerous for wandering around, but still having the feeling of being isolated from civilization. Just a normal woods .. but evil ;)

3 Answers
3

Weather: With the change in seasons, occasionally you will have a warm day that then gets very cold when a front comes through. Hypothermia is a danger.

Mechanical injury: If the characters are walking down a hill after the leaves start falling, a rain shower can cause those leaves to get slick causing characters to fall and sprain ankles, break bones or cut themselves on a somewhat sharp rock .

Rutting season: Deer may not kill you but Moose are VERY territorial during rutting season

Hibernation prep: Bears are likely to not eat players due to hunger but may be trying to find a hibernation spot and get spooked and attack out of fear.

Food scarcity: Since this is going to be far removed from civilization, if the players don't pack enough rations or can't find enough game, then bellies get empty.

Water scarcity: About the middle to end of fall, average precipitation drops until next spring. Therefore river levels go down, some creeks dry up, etc. But more of a concern during mid-late winter

Disease: Cold/Flu season starts sometime autumn to winter. A cold or flu working its way through the party would probably not win you any fans amongst your players.

Temperature: If the party gets out there with summer gear and the elevation changes much they will find themselves in very cold conditions. Not dangerous in itself but it makes many other dangers more dangerous. If you are cold, you don't think clearly that you are going down the hill too fast and risking mechanical injury, or care that you are sweating too much, or think about finding water/food, etc.

Add in other cases that would be problematic year-round, such as cliffs that are mostly concealed from view until you take one step too many.

Forests aren't particularly dangerous for the prepared. If you want to know what could possibly be dangerous at all given a lack of preparation or available technology/magic, then your best source is to look at wilderness survival handbooks for what the experts prepare against.

Googling for "wilderness survival handbook" gets some hits, though your local library is going to be full of great guides as well. Reading about the bright lights of survival techniques will reveal the dark shadows of potential sources of death. The first hit on the search was wilderness-survival.net, so I'm going to be looking at that as inspirations for some examples:

Panic. The first key to surviving is to keep your wits about you when the trip turns bad. Getting yourself lost, losing equipment, splitting up, being reckless and causing further injury—these are all ways that panic can increase your chances of other ways to die coming to visit. Making panic an actual danger is going to be hard in an RPG context, but depending on your system this might be the most powerful first line of crap hitting the fan. If your system doesn't mechanise the consequences of emotional responses though, and you're not sure you can pull it off with unstructured narrative without angering the players, skip this.

Water-borne disease. When you're in the wilderness you boil your water, purify it with filters, or sterilise it with iodine. Untreated water can kill you, and boy howdy do you need to drink a lot more than you can carry when you're trekking overland.

Freezing to death. There's a reason that every survival guide has entire sections on fire starting and building shelters for you and your fire. If you're in a temperate forest, night can be cold and you're might just die of exposure, so being capable of building a fire and keeping the wind/rain off it is important. Fortunately most fantasy-setting characters have a default level of experience simply because fire-building is as common as knowing how to drive in a modern setting. Still, adverse conditions that they'd rarely ever learn to mitigate for fires at the homestead – rain, wind, wet fuel – can be problems.

Dying of burns. Even if you know how to build a fire in less than ideal conditions, how to build a safe fire outside a fireplace is a learned skill. One good burn can kill you without modern medicine or healing magic.

Getting stuck. The problem with injury in the wilderness isn't just that you're injured and might need attention to prevent infection or death, but it's also that many injuries inhibit mobility. A broken leg that no-one knows how to splint can keep a party stuck in one place, which makes finding food, water, and help harder. A victim of a "simpler" injury or splinted broken leg might be able to walk, but pain, infection, and the simpler exhaustion of being injured can slow the group down significantly, potentially stretching an exit from the wilderness from a span of time that's within supply limits to something that would starve the group if it stayed with the injured individual.

And these are just throw-away examples from looking at the headings on that site! Doing this more systematically with an in-depth reading of a good survival handbook will get you even more and more finely-detailed ways that characters can be threatened by a forest.

And of course, once the wilderness has started to kill you, that's when many of the otherwise-non-threatening predators will take an interest…

If playing fantasy, a great and pretty threat is to have some elves or orcs patrol their territory or ambush the characters.
Mysterious ruins covered by moss and wild vegetals could host some undead or mechanic wardens, or badits could hide in the nearby caves.

Hungry animals on the hunt are a good choice, but a boar female with her piglets could be equally dangerous.

Depending on the system some of these treats could be more a hussle than a real danger.
Throw in a dragon patrolling his territory if everything else goes bad.

+1 because One - at first my question was a lot more vague, and this answer was on-topic (now it is not, and bound to attract downvotes, unfortunately). And second, because It convinced me to add a fantasy element - turns out the temple of undead would tie several loose story ends one to another. Thanks, Zachiel.
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VoracOct 22 '12 at 7:08